Green tea / EGCG
mg/day EGCG or catechins
Green tea as a drink, a powder, or an EGCG capsule. Decaffeinated extracts still count; a pure caffeine milligram count does not.
The catechin named most often is epigallocatechin-3-gallate (EGCG). Decaffeinated extracts still belong here because the trial is dosing tea catechins. A caffeine capsule is a different exposure, and a rye bread or candy that merely contains green tea is a different food.
Also called EGCG, green tea extract, catechins.
Connected relationships
Randomized trial · Contested
Green tea / EGCG→Cognitive performance
Higher Green tea / EGCG moves Cognitive performance only in some conditions. Read the mechanism.
Wightman 2012 found that 135 or 270 mg of epigallocatechin gallate did not change computerised cognitive tasks or mood versus placebo in 27 healthy adults, though frontal blood flow fell at the lower dose. Dietz 2019 saw a small attention and psychomotor-speed rise after a matcha drink in 23 people.
Randomized trial · Moderate
Green tea / EGCG→Insulin resistance (HOMA-IR)
A rise in Green tea / EGCG does not identify a change in Insulin resistance (HOMA-IR).
Brown 2009 found that 400 mg of EGCG twice a day for eight weeks did not change insulin sensitivity, insulin secretion, or glucose tolerance versus lactose in 88 overweight or obese men. Hsu 2011 and Fukino 2006 also found no between-group HOMA difference after a green-tea extract or powder.
Sources
- EL Wightman et al. (2012). Epigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigation.
- C Dietz et al. (2019). An intervention study on the effect of matcha tea, in drink and snack bar formats, on mood and cognitive performance.
- AL Brown et al. (2009). Effects of dietary supplementation with the green tea polyphenol epigallocatechin-3-gallate on insulin resistance and associated metabolic risk factors: randomized controlled trial.
- CH Hsu et al. (2011). Does supplementation with green tea extract improve insulin resistance in obese type 2 diabetics? A randomized, double-blind, and placebo-controlled clinical trial.
- Y Fukino et al. (2006). Randomized controlled trial for an effect of green tea consumption on insulin resistance and inflammation markers.